Temperature corrected integrating analog-to-digital converter

Abstract

Disclosed is an integrating analog-to-digital converter characterized as a function of the temperature. The characterizing information is processed in a manner to correct the digital information before the digital information is subsequently processed by other system processors.

The embodiments of an invention in which an exclusive property or right is claimed are defined as follows: 
     
       1. An integrating analog-to-digital converter for converting an analog input signal to a digital representation thereof, said integrating analog-to-digital converter comprising: analog means for generating an analog input signal;   first temperature sensing means for providing an analog means temperature output signal representative of the temperature of said analog means;   first storage means for storing first information descriptive of the temperature characteristic of said analog means so that a signal representative of said analog means may be corrected as a function of said analog means temperature output signal and said first information;   circuit means responsive to said analog input signal for providing an output signal which changes between at least first and second levels having a frequency characteristic as a function of the integral of said analog input signal;   at least a first counter means responsive to said circuit means output signal for counting said signal changes thereof changing from said first level to said second level, and providing a first counter means output representative of said count;   second temperature sensing means for providing a circuit means temperature output signal representative of the temperature of a selected ambient temperature region in proximity to said circuit means; and   second storage means for storing circuit second information descriptive of the temperature characteristic of said circuit means so as to be descriptive of the performance of said integrating analog-to-digital converter so that at least said first counter means may be corrected as a function of said circuit means temperature output signal and said second information.   
     
     
       2. The integrating analog-to-digital converter of claim 1 further including digital signal processing means operative for generating a digital output representative of a function of said first counter means output and a scalar quantity where said scalar quantity is a function of said converter information and said circuit means temperature output signal. 
     
     
       3. The integrating analog-to-digital converter of claim 1 where said temperature characteristic of said circuit means is related to scale factor which relates the analog input signal with said first counter means output. 
     
     
       4. The integrating analog-to-digital converter of claim 1 wherein said second information includes coefficients of a polynomial which characterize the temperature characteristic of said temperature characteristic of said circuit means descriptive of the performance of said integrating analog-to-digital-converter. 
     
     
       5. The integrating analog-to-digital converter of claim 4 where said temperature characteristic of said circuit means is related to scale factor which relates the analog input signal with said first counter means output. 
     
     
       6. The integrating analog-to-digital converter of claim 1 wherein: said circuit means is further responsive to said analog input signal for providing said first output signal as a function of the integral of positive values of said analog input signal, and a second output signal which changes between at least first and second levels having a frequency characteristic as a function of the integral of negative values of said analog input signal; and   said converter further including a second counter means responsive to said circuit means second output signal for counting said signal changes thereof changing from said first level to said second level, and providing a second counter means output representative of said second counter count.   
     
     
       7. The integrating analog-to-digital converter of claim 6 further including digital signal processing means operative for generating a digital output representative of: (i) a function of said first counter means output and a first scalar quantity corresponding to positive values of said analog input signal, where said first scalar quantity is a function of said second information corresponding to positive values of said analog input signal and said circuit means temperature output signal; and   (ii) a function of said second counter means output and a second scalar quantity corresponding to negative values of said analog input signal, where said second scalar quantity is a function of said second second information corresponding to negative values of said analog input signal and said circuit means temperature output signal.   
     
     
       8. The integrating analog-to-digital second of claim 7 wherein: said converter information includes first set of coefficients of a first polynomial which characterize said first scalar quantity where said first scalar quantity is a function of said converter temperature output signal for positive values of said analog input signal; and   a second set of coefficients of a second polynomial which characterize said second scalar quantity where said second scalar quantity is a function of said converter temperature output signal for negative values of said analog input signal.   
     
     
       9. The integrating analog-to-digital converter of claim 6 further including digital signal processing means operative for generating: (i) a digital output represented of a function of said first counter means output and a first scalar quantity corresponding to positive values of said analog input signal, where said first scalar quantity is a function of said converter information corresponding to positive values of said analog input signal and said circuit means temperature output signal; and   (ii) a digital output representative of a function of said second counter means output and a second scalar quantity corresponding to negative values of said analog input signal, where said second scalar quantity is a function of said converter information corresponding to negative values of said analog input signal and said circuit means temperature output signal.   
     
     
       10. The integrating analog-to-digital converter of claim 9 wherein said second information includes: a first set of coefficients of a first polynomial which characterize said first scalar quantity where said first scalar quantity is a function of said converter temperature output signal for positive values of said analog input signal; and   a second set of coefficients of a second polynomial which characterize said second scalar quantity where said first scalar quantity is a function of said converter temperature output signal for negative values of said analog input signal.   
     
     
       11. The integrating analog-to-digital converter of claim 1 wherein said second information includes a first set of coefficients of a first polynomial defining said first selected quantity, said first selected quantity being a first scalar quantity where said first scalar quantity is a function of said converter temperature output signal and said first set of coefficients for correcting said first counter means output by said first scalar quantity. 
     
     
       12. An apparatus for obtaining acceleration information derived from sensed acceleration along a predetermined input axis, said apparatus comprising: an analog accelerometer for providing an analog output signal having sign and magnitude representative of the acceleration sensed by said analog accelerometer along the input axes thereof;   an accelerometer temperature sensing means for providing an accelerometer temperature output signal representative of the temperature of said analog accelerometer;   means for storing accelerometer information descriptive of the temperature characteristic of at least one selected quantity descriptive of the performance of said analog accelerometer;   an integrating digital-to-analog converter for converting said accelerometer analog output signal to a digital representation thereof, said integrating analog-to-digital converter including, an integrator-digitizer having an input means responsive to said accelerometer analog output signal, and having at least one output signal for providing a selected signal change between first and second levels having a frequency characteristic as a function of the integral of said accelerometer analog output signal,   integrator-digitizer temperature sensing means for providing an integrator-digitizer temperature output signal representative of a selected ambient temperature region in proximity to one or more analog circuit components of said integrator-digitizer means;   means for storing integrator-digitizer information representative of the temperature characteristic of at least one selected quantity descriptive of the performance of said integrator-digitizer at least first output signal, and   at least a first counter means for providing a first counter output representative of an accumulative count of said selected signal change of said integrator digitizer output signal; and   signal processor and control means responsive to (i) said first counter means output signal, (ii) said accelerometer temperature output signal, (iii) said integrator-digitizer temperature output signal, (iv) said accelerometer information, and(v) said integrator-digitizer information for generating acceleration information sensed by said accelerometer as a function of said first counter means output signal corrected by a first scalar quantity which is a function of said integrator-digitizer temperature output signal and said integrator-digitizer information, and by an accelerometer scalar quantity which is a function of said accelerometer temperature output signal and said accelerometer information.     
     
     
       13. The apparatus of claim 12 further including digital signal processing means operative for generating a digital output representative of a function of said first counter means output and a first scalar quantity where said first scalar quantity is a function of said converter information and said circuit means temperature output signal. 
     
     
       14. The apparatus of claim 12 where said first scalar quantity is related to scale factor which relates the accelerometer analog output signal with said first counter means output. 
     
     
       15. The apparatus of claim 12 wherein said converter information includes coefficients of a polynomial which characterize the temperature characteristic of said first scalar quantity which is descriptive of the performance of said integrating analog-to-digital-converter. 
     
     
       16. The apparatus of claim 12 wherein said integrator-digitizer is further responsive to said accelerometer analog output signal for providing said first output signal as a function of the integral of positive values of said accelerometer analog output signal, and a second output signal which changes between at least first and second levels having a frequency characteristic as a function of the integral of negative values of said accelerometer analog output signal, and said converter further including a second counter means responsive to said integrator-digitizer second output signal for counting said signal changes thereof changing from said first level to said second level, and providing a second counter means output representative of said second counter count. 
     
     
       17. The apparatus of claim 12 wherein said signal processor and control means is operative for generating: (i) a digital output representative of a function of said first counter means output and a first scalar quantity corresponding to positive values of said accelerometer analog output signal, where said first scalar quantity is a function of said converter information corresponding to positive values of said accelerometer analog output signal and said circuit means temperature output signal, and   (ii) a digital output representative of a function of said second counter means output and a second scalar quantity corresponding to negative values of said accelerometer analog output signal, where said second scalar quantity is a function of said converter information corresponding to negative values of said accelerometer analog output signal and said circuit means temperature output signal.   
     
     
       18. The integrating analog-to-digital converter of claim 17 wherein said converter information includes a first set of coefficients of a first polynomial defining said first selected quantity, said first selected quantity being said first scalar quantity which is a function of said converter temperature output signal and said first set of coefficients for correcting said first counter means output by said first scalar quantity. 
     
     
       19. The apparatus of claim 12 wherein said signal processor and control means is operative for generating a digital output representative of: (i) a function of said first counter means output and a first scalar quantity corresponding to positive values of said accelerometer analog output signal, where said first scalar quantity is a function of said converter information corresponding to positive values of said accelerometer analog output signal and said circuit means temperature output signal, and   (ii) a function of said second counter means output and a second scalar quantity corresponding to negative values of said accelerometer analog output signal, where said second scalar quantity is a function of said converter information corresponding to negative values of said accelerometer analog output signal and said circuit means temperature output signal.   
     
     
       20. The integrating analog-to-digital converter of claim 17 wherein said converter information includes: first set of coefficients of a first polynomial which characterize said first scalar quantity where said first scalar quantity is a function of said converter temperature output signal for positive values of said accelerometer analog output signal; and   a second set of coefficients of a second polynomial which characterize said second scalar quantity where said second scalar quantity is a function of said converter temperature output signal for negative values of said accelerometer analog output signal.   
     
     
       21. The integrating analog-to-digital converter of claim 12 wherein said converter information includes: a first set of coefficients of a first polynomial which characterize said first scalar quantity where said first scalar quantity is a function of said converter temperature output signal for positive values of said accelerometer analog output signal; and   a second set of coefficients of a second polynomial which characterize said second scalar quantity where said second scalar quantity is a function of said converter temperature output signal for negative values of said accelerometer analog output signal.   
     
     
       22. An Analog-to-digital converter for converting an analog signal from an analog sensing device to a digital signal, the converter comprising: circuit card means, including: analog circuit components which serve, in part, as an integrator-digitizer circuit for providing an output signal defined by a selected signal change between at least first and second levels having a frequency   characteristic as a function of said analog signal; and   a temperature sensing means for providing a first circuit card temperature output signal representative of the temperature of said analog sensing device and a second circuit card temperature output signal representative of the temperature of a selected region of said circuit card;   means for storing circuit card information descriptive of the temperature characteristics of said analog sensing device and of at least one selected quantity descriptive of the performance of said integrator-digitizer;   at least a first counter means for providing a first counter output representative of an accumulation over a selected time period of said signal changes of said first and second circuit card temperature output signals; and   correction means independently responsive to said first and second circuit card temperature output signals for separately correcting said first counter output.